Topic overview

Start with the big picture

Electrical synapses allow direct ion flow and are described as fast and bidirectional, while chemical synapses use neurotransmitters and are generally slower and unidirectional. In chemical transmission, an action potential reaches the nerve terminal, calcium enters, and vesicles release neurotransmitter into the synaptic cleft. Binding at postsynaptic receptors produces an excitatory or inhibitory response; signaling ends through reuptake, enzymatic breakdown, or diffusion. The topic distinguishes depolarizing EPSPs from hyperpolarizing IPSPs and introduces major neurotransmitters, including glutamate, GABA, glycine, acetylcholine, and norepinephrine. It also previews synaptic plasticity, neuromuscular junction signaling, and clinical links such as myasthenia gravis, botulism, SSRI action, and reduced dopamine in Parkinson’s disease.